Carry out the method
for liquid chromatography, using the following solutions.
(1) Weigh the contents of 20 capsules and
grind to a fine powder. Disperse a quantity of the powder containing 20 mg of
Omeprazole in 150 mL of mobile phase, mix with the aid of ultrasound for 30
minutes, dilute with sufficient mobile phase to produce 200 mL, mix and filter
and further dilute 10 volumes to 100 volumes with the mobile phase.
(2) 0.0010 % w/v of omeprazole ws in the
mobile phase.
Standard solution : Weigh accurately
about 20 mg of Omeprazole ws &
tranafer it into 200 ml volumetric flask & dissolve it into mobile phase
and dilute with moblile phase to volume .Further dilute 10 ml to 100 ml with
mobile phase.
(3) Mix 10 mg each of omeprazole ws and
omeprazole impurity D in mobile phase and dilute to 100 mL with the same
solvent.
CHROMATOGRAPHIC
CONDITIONS
(a) Use a stainless steel column (15
cm × 4.6 mm) packed with octylsilyl silica gel for chromatography (5 µm)
(Nucleosil RP8 is suitable).
(b) Use isocratic elution using the
mobile phase
(c) Use a flow rate of 1 mL per minute.
(d) Use an ambient column temperature.
(e) Use a detection wavelength of 280
nm.
(f) Inject 40 µL of each solution.
(g) Allow the chromatography to proceed
for 3 times the retention time of omeprazole.
SYSTEM SUITABILITY
The test is not valid unless, in the
chromatogram obtained with solution (3), the resolution factor between the
peaks due to impurity D and omeprazole is greater than 3.0.
DETERMINATION OF
CONTENT
Calculate the content of C17H19N3O3S
in the capsules from the chromatogram obtained and using the declared content
of C17H19N3O3S in omeprazole ws.
Assay:
